Filter For Removing Sediment From Water

ABSTRACT

A system for removing sediment from water is disclosed. The exemplary embodiments described herein disclose a system comprising a filter chamber, having a deck positioned inside to divide it into an upper chamber and a lower chamber. The deck may have a plurality of holes to hold filtration elements and also may have a ridge or a skirt or both. An inlet line may be tangentially connected to the filter chamber and introduce influent liquid into the filter chamber below the deck and outside of the skirt.

This is a continuation-in-part of U.S. patent application Ser. No.11/839,303, which was filed on Aug. 15, 2007 and entitled “FILTER FORREMOVING SEDIMENT FROM WATER,” the disclosure of which is incorporatedby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an apparatus, system, andmethod for removing sediment from water, and, more particularly, to anelongated filtratable element used for removing sediment fromstormwater.

2. Description of the Related Art

Stormwater runoff is rainfall or snowmelt that travels over the groundor impervious surfaces—roofs of buildings, homes and sheds, roadways,parking lots, sidewalks and driveways—and drains into natural or manmadedrainage ways. In some cases, stormwater runoff drains directly intobodies of water. Stormwater runoff does not usually receive anytreatment before it enters streams, lakes, and other surface waters, andit is a major source of water pollution. For example, various harmfulpollutants, such as pesticides, fertilizer, litter, car oil, bacteria,trace metals, and sediment, are washed off with stormwater runoff intostorm drains, or directly into streams, rivers, and lakes.

One of the harmful pollutants of major concern is sediment. Sediment issoil particles from stream banks, construction sites, and other areas,that are dislodged by stormwater runoff and deposited into streams,lakes, and rivers. Sediment accumulates in water bodies and destroysfeeding grounds for aquatic life, clogs fish gills, blocks light,increases water temperature, and can cause other adverse environmentalimpacts.

Currently, sedimentation-based tanks are used to remove the majority ofsediment that is dislodged by stormwater runoff. Sedimentation-basedtanks, however, cannot completely remove all of the fine sediment fromstormwater because of the required settling time needed for finesediment to be removed from stormwater. For example, settling out thefine sediment in stormwater would require a large and uneconomicalsedimentation-based tank. Therefore, in addition to sedimentation-basedtanks, granular media filter systems are used downstream ofsedimentation-based tanks to remove fine sediment. Granular media filtersystems utilize different types of granular media to trap fine sedimentin the interstitial gaps formed between the granular media. However, asthe fine sediment continues to accumulate, the interstitial gapseventually clog and must be frequently recharged. Granular media filtersystems can be partially recharged through pressurized backwashing, butpressurized backwashing piping and controls are complicated andexpensive.

In addition to granular media filter systems, a variety of other filtersystems are available for filtering contaminated fluids. For example,filter cloths consisting of pile threads may be used, U.S. Pat. No.6,103,132, which is incorporated by reference herein. While these typesof filters and others like them have their merits, they also have theirdrawbacks. For example, the filters have a small amount of surface areaavailable for trapping fine sediment. As a result, during high flowevents, the filter systems quickly clog, causing the stormwater runoffto back up. In addition to filter cloths, flexible hose-type filterelements have been used, U.S. Pat. No. 4,163,724, which is incorporatedby reference herein. Such hose-type filter elements, however, rely onpressurized flow to effect separation.

SUMMARY OF THE INVENTION

A system for removing sediment from water is disclosed. According to oneembodiment of the present invention, the system comprises a filterchamber defining an internal chamber; a deck positioned within theinternal chamber and dividing the filter chamber into an upper chamberand a lower chamber, the deck having a plurality of holes formedtherein, each hole adapted to receive a filtration element therein; andan inlet line for communicating an influent liquid to the filter chamberat a location that is below the deck; wherein the inlet line ispositioned such that the influent liquid is introduced tangentially intothe filter chamber.

According to another embodiment of the present invention, the systemcomprises a filter chamber defining an internal chamber; a deckpositioned within the internal chamber and dividing the filter chamberinto an upper chamber and a lower chamber, the deck having a pluralityof holes formed therein, each hole adapted to receive a filtrationelement therein; an inlet line for communicating an influent liquid tothe filter chamber; and a ridge positioned on a top surface of the deck,wherein the ridge forms a perimeter on the top surface of the deck.

According to another embodiment of the present invention, the systemcomprises a filter chamber defining an internal chamber; a deckpositioned within the internal chamber and dividing the filter chamberinto an upper chamber and a lower chamber, the deck having a pluralityof holes formed therein, each hole adapted to receive a filtrationelement therein; an inlet line for communicating an influent liquid tothe filter chamber; and a skirt positioned on a bottom surface of thedeck.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, the objectsand advantages thereof, reference is now made to the followingdescriptions taken in connection with the accompanying drawings inwhich:

FIG. 1A is a perspective view of a elongated filtratable elementaccording to one embodiment of the present invention;

FIG. 1B is a perspective view of a elongated filtratable elementaccording to one embodiment of the present invention;

FIG. 1C is a perspective view of each component that comprises afiltratable element according to one embodiment of the presentinvention;

FIG. 1D is a perspective view of a partially assembled filtratableelement according to one embodiment of the present invention;

FIG. 1E is a perspective view of fully assembled filtratable elementaccording to one embodiment of the present invention;

FIG. 2 is a perspective view of a preassembled filter mat according toone embodiment of the present invention;

FIGS. 3A-3C are perspective views of magnified sections of a filter mataccording to one embodiment of the present invention;

FIGS. 4A-4B are perspective views of a filtration cartridge according toone embodiment of the present invention;

FIG. 5A-5B are perspective views of a filtration cartridge according toone embodiment of the present invention;

FIGS. 5C-5D are perspective views of a lid for the filtration cartridgeaccording to one embodiment of the present invention;

FIG. 6 is a perspective view of a shaking mechanism according to oneembodiment of the present invention;

FIG. 7 is a perspective view of a filtering system according to oneembodiment of the present invention;

FIG. 8 is a perspective view of the inlet device according to oneembodiment of the present invention;

FIGS. 9A-9B are perspective views of the filtration system according toone embodiment of the present invention;

FIGS. 10A-10B are perspective views of a filtration system according toone embodiment of the present invention;

FIG. 11 is a perspective view of a filtration system with a backwashingmechanism according to one embodiment of the present invention;

FIGS. 12A-12B are perspective views of a valve assembly according to oneembodiment of the present invention;

FIG. 13 is a perspective view of a filtration system with a backwashingmechanism with a partition, where accumulated filtrate is above eachvalve assembly according to one embodiment of the present invention;

FIG. 14 is a perspective view of a filtration system with a backwashingmechanism where each elongated filtratable element has been backwashedaccording to one embodiment of the present invention;

FIG. 15 is a perspective view of a deck for a filtration systemaccording to one embodiment of the present invention;

FIG. 16 is a side perspective view of a filtration system according toone embodiment of the present invention;

FIG. 17 is a top perspective view of a filtration system according toone embodiment of the present invention; and

FIG. 18 is a bottom perspective view of a filtration system according toone embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Although the present invention is described in the context of stormwaterfiltration, the invention is not so limited. Rather, the presentinvention has application as a filter media for many types of liquid,including water. Stormwater runoff generally has an “organic portion”and an “aqueous portion.” The organic portion of stormwater runofftypically has a relatively high amount of sediment, which includes, forexample, dislodged soil particles from stream banks, construction sites,and other areas, as well as other suspended particles that may or maynot be organic. The aqueous portion of stormwater is primarily water. Asused herein, the term “downstream” in a process system means later inthe direction of general process or fluid flow, and the term “upstream”means earlier in the direction of general process or fluid flow.

Disclosed embodiments of the present invention and their advantages maybe understood by referring to FIGS. 1-14, wherein like referencenumerals refer to like elements.

In accordance with an embodiment of the present invention describedherein is an elongated filtratable element that has a large amount ofsurface area for filtering a substantial amount of fine sediment fromstormwater. The disclosed filtratable element can be used individuallyor in combination with other filtratable elements. And, the filtratableelements can be combined with current stormwater filtering systems toimprove efficiency.

According to one embodiment of the present invention, the elongatedfiltratable element may be a tubular element or hollow tube with apermeable fiberglass filter media that surrounds a flexible inner core.The fiberglass filter media may have a porosity such that it allows theaqueous portion of stormwater to pass through, while trapping sediment.

Referring to FIGS. 1A-1E, perspective views of elongated filtratableelement 100 and its components are shown. Referring to FIG. 1A,according to one embodiment, each elongated filtratable element 100, ortentacle, includes three general components: support member 101, filtermat 102, and outer casing 103. In general, support member 101 preventsthe surrounding filter mat 102 from collapsing. Filter mat 102 consistsof any permeable filtratable material that surrounds inner core 101.Filter mat 102 may be adapted to filter a substantial amount of finesediment from stormwater runoff. Outer casing 103 protects filter mat102 from abrasion. Each component will be described in greater detailbelow.

In one embodiment, support member 101 may be adapted to be an inner corethat serves as a frame for elongated filtratable element 100, and may beprovided to prevent elongated filtratable element 100 from collapsingupon itself. Support member 101 may comprise a flexible support tubemade of any water permeable member, such as a polymer membrane. Whileany water permeable polymer materials may be used, in one embodiment,support member 101 may be made of a plastic, such as polyurethane,acrylate, polypropylene or polyethylene.

In another embodiment, support member 101 may be made of any waterimpermeable member. Support member 101 may be adapted so that it has anegligible effect on sediment removal and has negligible head lossassociated with it under typical flows.

In another embodiment, support member 101 may comprise a more rigid,even an inflexible, support structure made of metal or plastic that isadapted to allow for the passage of stormwater. Support member 101 maybe manufactured by way of plastic injection molding, as is well known inthe art.

In still another embodiment, support member 101 may be an inner framecomprised of support rings or rods, or a combination of both. In stillanother embodiment, support member 101 may be formed as an integralcomponent of filter mat 102. Support member 101 may be of any suitableshape, and for example, may be round, square, or rectangular in shape.Support member 101 may be made of a corrosion-resistant material, as iswell known in the art. Other sizes, shapes, or materials may be used forsupport member 101 as necessary and/or desired.

Referring to FIG. 1B, support member 101 is shown according to anotherembodiment of the present invention. In this embodiment, support member101 may be a flexible coil that serves as the foundation for theelongated filtratable element 100.

Filter mat 102 serves to filter and trap sediment and other particles instormwater. In one embodiment, filter mat 102 may comprise a tube ofnon-woven filtration media that surrounds support member 101, ifprovided. In one embodiment, shown in FIG. 2, filter mat 102 may becomprised of two parts: backing mesh 202 and fiberglass batting 201.Backing mesh 202 may include a comparatively course, non-woven plasticsupport layer, and fiberglass batting 201 may include a plurality ofindividual fiberglass fibers.

The use of fiberglass batting 201 provides several advantages. Forexample, fiberglass batting 201 may be high in surface area,self-cleanable, easily maintained, durable, and economical.

In order to create filter mat 102, a plurality of fiberglass fibers, ofthe same or different diameters and/or lengths, may be attached tobacking mesh 202. In another embodiment, filter mat 102 may be comprisedof any natural filaments or synthetic filaments. For example, filter mat102 may also comprise graphite filaments, metallic filaments, glassfilaments, polymer fibers, or any other suitable material as necessaryand/or desired.

In one embodiment, filter mat 102 may have a relatively high porosity(i.e., it allows relatively large particles to pass). For example,backing mesh 202 may be comprised of 10-20 μm plastic fibers that formopenings of more than about 200 μm, and fiberglass batting 201 may becomprised of less than 1 μm fiberglass fibers that are loosely packed.

In another embodiment, filter mat 102 may have a relatively low porosity(i.e., it allows only relatively small particles to pass). In thisembodiment, backing mesh 202 may be comprised of 10-20 μm plastic fibersthat form openings of less than about 200 μm, and fiberglass batting 201may be comprised of less than 1 μm fiberglass fibers that are tightlypacked.

One of ordinary skill in the art can readily determine appropriate fiberlength, diameter, and percentage of porosity for filter mat 102depending on the expected stormwater flow rate and sediment particlesize.

Referring to FIG. 3A, a magnified portion of filter mat 102 is shown,according to one embodiment of the present invention. In one embodiment,individual filter media filaments 301, made of any suitable material,are attached to backing mesh 202. In the aggregate, individual filaments301 comprise fiberglass batting 201. When filter mat 102 is exposed tostormwater flow, as shown in FIG. 3B, fiberglass batting 201 may bepressed against backing mesh 202 to create a compact, yet permeable,filter bed. When filter mat 102 is backwashed, as shown in FIG. 3C anddescribed in greater detail below, filtrate flows through eachfiltratable element 100 in the opposite direction, causing filaments 301of fiberglass batting 201 to be forced away from backing mesh 202.Backwashing regenerates each element 100 by removing a substantialamount of trapped sediment.

Referring to FIGS. 1C-1E, filter mat 102 may be formed into a tube.Filter mat 102 may be adapted to surround support member 101 so thatbacking mesh 202 faces or contacts support member 101. Filter mat 102may consist of two half-cylinders. The half-cylinders may be connectedby a hinge. As an example, filter mat 102 may be snap-fitted oversupport member 101, as best shown in FIG. 1D. Filter mat 102 may also beadapted such that it is not a rigid element, and it may be folded oversupport member 101. Outer casing 103 may be adapted to surround filtermat 102. In one embodiment, outer casing 103 may consist of twohalf-cylinders. The half-cylinders may be connected by a hinge. As anexample, outer casing 103 may be snap-fitted over filter mat 102, asbest shown in FIG. 1E.

Referring back to FIGS. 1A and 1B, spacers 105 may be disposed betweensupport member 101 and filter mat 102. Spacers 105 may be used to fastenor attach filter mat 102 to support member 101. Spacers 105 may alsoallow for the aqueous portion of the stormwater to freely permeatethrough filter mat 102. Spacers 105 may be made of the same material assupport member 101, or any other suitable material. The size, shape,number, and location of spacers 105 may be varied as necessary and/ordesired.

Outer casing 103, according to one embodiment of the present invention,protects filter mat 102 and fiberglass batting 201 from abrasion.Because stormwater runoff may contain a substantial amount of sediment,it has a tendency to abrade and destroy unprotected filter media as itpermeates through. Outer casing 103 may also protect filter mat 102 fromabrasion that may be caused by large debris or occur during normalhandling of the filtratable element 100 or groups of elements, such asduring typical packaging, transportation, and installation activities.In one embodiment, outer casing 103 may be a wire mesh screen. Inanother embodiment, outer casing 103 may be a nylon screen. The meshsize of outer casing 103 may be adapted such that the screen does nottrap sediment, nor become clogged. One of ordinary skill in the art canreadily determine the appropriate mesh size. Further, in addition toprotecting filter mat 102 from abrasion, outer casing 103 adds to thestability and strength of the elongated filtratable element 100.

In one embodiment, elongated filtratable element 100 may be constructedwithout outer casing 103. Under some flow conditions and depending onthe amount of sediment expected in the stormwater runoff, outer casing103 may be unnecessary. Moreover, filter mat 102 may be constructed of amaterial that reduces the risk of abrasion and eliminate the need forouter casing 103. One of ordinary skill in the art can readily determinethe need for outer casing 103.

In one embodiment, support member 101, filter mat 102, and outer casing103 may be coated or treated with an antimicrobial agent. Antimicrobialagents are materials that are able to reduce or eliminate the microbialgrowth, e.g., bacteria, yeasts, molds. Microbes, if left untreated, mayreduce the separation efficiency of filtratable elongated element 100,and eventually clog the filter media. In one embodiment, chitosan may beintroduced into the stormwater or used to coat filtratable element 100to prevent or reduce microbial degradation. Chitosan causes the finesediment particles to bind together and may also remove phosphorus,heavy minerals, and oils from stormwater. Other antimicrobial agents mayalso be used as necessary and/or desired.

Elongated filtratable element 100 may be adapted to increase theavailable surface area for removing sediment. In one embodiment, thismay involve pleating, crimping, or finning the surface of elongatedfiltratable element 100. Other constructions that increase the surfacearea may be used as necessary and/or desired.

In one embodiment, elongated filtratable element 100 may be providedwith a packing or granular filtration media, for example, sand,polyethylene beads, clay, perlite, etc, in order to adsorb contaminantsthat might be present in stormwater.

Referring to FIGS. 4A and 4B, filtration cartridge 400 is shown,according to embodiment of the present invention. Filtration cartridge400 may include two general components: central manifold 401 and aplurality of elongated filtratable elements 100. Central manifold 401may be a deck with a plurality of holes 402, adapted to receive aplurality of elongated filtratable elements 100. Central manifold 401may also be considered a plate. Central manifold 401 may also be a tubehaving top and bottom plates that are separated by a gap. The tube maybe of any suitable shape. For example, it may be cylindrical or cubical.

In one embodiment, central manifold 401 may be comprised of animpermeable plastic, and it may be of any suitable shape. For example,central manifold may be round, square, or rectangular in shape. In oneembodiment, the shape of central manifold 401 may be selected tocorrespond to the opening in which it is to be placed.

In one embodiment, central manifold 401 may also be coated with anantimicrobial agent to prevent unwanted microbe growth, as discussedabove.

Central manifold 401 may include a plurality of holes 402, with eachhole 402 being sized and adapted to receive at least one elongatedfiltratable element 100.

Referring to FIGS. 5A and 5B, according to one embodiment of the presentinvention, central manifold 401 of filtration cartridge 400 may have asidewall with at least one notch 403. Notch 403 may be provided so thatcentral manifold 401 may be easily fitted into stormwater filtrationsystems.

Referring to FIGS. 5C and 5D, filtration cartridge 400 may be fittedwith a lid 404. Lid 404 may have at least one hole 406 for restrictingflow through elongated filtratable elements 100 that are attached tocentral manifold 401. In one embodiment, lid 404 may have only one hole406. In another embodiment, lid 404 may have two holes 406. Othernumbers and arrangements of holes 406 may be used as necessary and/ordesired.

Lid 404 may have threaded walls. Each filtration cartridge 400 may havea ring (not shown) that fits around cartridge 400 so that lid 404 may beattached to cartridge 400. Each filtration cartridge 400 with lid 404attached thereto may be installed into a filtration system. Lid 404 maybe of any suitable shape. Further, the amount of space between the topof filtration cartridge 400 and the bottom of lid 404 may be changed asnecessary and/or desired.

With reference to FIGS. 1, 4A, 4B, 5A and 5B, each elongated filtratableelement 100 may be fitted with a cap 104 for attaching each elongatedfiltratable element 100 to central manifold 401. For example, in oneembodiment, holes 402 may be sized to hold 1″ diameter elongatedfiltratable elements 100. In another embodiment, each hole 402 may beadapted to hold more than one elongated filtratable element 100.Further, the shape of holes 402 may vary to accommodate differentlyshaped elongated filtratable elements 100.

In one embodiment, holes 402 are open and uncovered so as to reduce thechance of additional clogging. Although, in another embodiment, holes402 can be provided with a filter, for example, a layer of porous media,to provide an additional filtration. The porous media may also be ableto adsorb or to react with dissolved components in the water.

In one embodiment, filtration cartridge 400 may include a substantialnumber of filtratable elements 100. For illustration only, more than 100elongated filtration elements 100 may be provided. More or fewerfiltration elements 100 may be provided. Each elongated filtrationelement 100 may be about 1″ in diameter, although each filtrationelement 100 may have a different diameter, length, and/or shape.

Filtration cartridge 400 may be of any size and shape to accommodatedifferent operating conditions. Filtration cartridge 400 may beassembled such that elongated filtration elements 100 dangle freely fromcartridge 400. Because each elongated element 100 may be flexible anddangle freely from cartridge 400, filter cartridge 400 may be easilymaintained by mechanical means, such as vibration and/or shaking.Moreover, if one elongated filtratable element 100 becomes clogged ordamaged, filtration cartridge 401 allows for it to be individuallyreplaced.

Referring to FIGS. 6A-6D, a shaking mechanism for filtration cartridge400 is shown, according to an embodiment of the present invention. Inone embodiment, shaking mechanism 600 may be an accessible,manually-operated mechanism that includes a hand crank 601, a shaft 602,a base 603, and a bar 604. Shaking mechanism 600 may be designed suchthat it causes at least one filtration cartridge 400 to rotate, therebyremoving any trapped sediment from each elongated element 100. Handcrank 601 may be adapted so that it extends above filtration cartridge400 and may be easily turned. Turning hand crank 601 causes shaft 602 torotate base 603. Bar 604 connects base 603 to a deck in which filtrationcartridge 400 may be installed. The rotating motion of filtrationcartridge 400 causes the freely dangling elongated filtratable elements100 to shake, which may remove trapped sediment. In another embodiment,shaking mechanism 600 may be automated. Other shaking and/or vibrationmechanisms may be used as necessary and/or desired.

Referring to FIG. 7, a filtration system 700 is shown, according to oneembodiment of the present invention. Filtration system 700 may includefive general components: a filtration chamber 701, an inlet line 702, aninlet device 703, one or more filtration cartridges 400, and an outletline 704. In general, one or more filtration cartridges 400 may beplaced inside filtration chamber 701. If more than one filtrationcartridge 400 is placed inside filtration chamber 701, a deck may beused. Inlet line 702 introduces stormwater into filtration chamber 701through inlet device 703, and outlet line 704 discharges the filtrate.

In one embodiment, filtration chamber 701 may house a single filtrationcartridge 400. Filtration chamber 701 may either be open to theatmosphere, or it may be enclosed. Further, filtration chamber 701 mayeither be located above-ground or underground. Filtration chamber 701may be of any conventional type or shape and may be constructed fromsteel, fiberglass, concrete, or plastic, or other suitable materials.

Filtration cartridge 400 may be flush with the walls of filtrationchamber 701 so as to prevent stormwater from seeping upwards betweenfiltration cartridge 400 and filtration chamber 701. Filtrationcartridge 400 may be fitted with a conformable seal to contact thesidewalls of filtration chamber 701 to prevent seepage.

In another embodiment, filtration chamber 701 may house a plurality offiltration cartridges 400, using a deck. One of ordinary skill in theart can readily determine the number of filtration cartridges, and,correspondingly, the number of elongated filtratable elements 100 neededfor a given operation. One advantage to filtration chamber 701 having aplurality of filtration cartridges 400 is that more filtrationcartridges 400 provides for more filtratable surface area, increasingthe operating life of and flow rate through filtration system 700. Inanother embodiment, filtration cartridge 400 may be configured or fittedin a different arrangement. For example, filtration cartridge 400 may beadapted to be horizontal or inverted. Further filtration cartridge 400may be located inside inlet line 702. Other configurations and locationsfor filtration cartridge 400 may be used as necessary and/or desired.

Referring to FIG. 8, inlet device 703 is shown, according to oneembodiment of the present invention. Inlet device 703 consists of a meshscreen 804, a deck 805, a weir 803, and a base 801. Base 801 may becomprised of a buoyant, impermeable material. Base 801 may have a hole807 formed through it to allow stormwater to fill filtration chamber701. In another embodiment, base 801 may be made of a porous materialinstead of having a hole. In one embodiment, weir 803 may be attached toand extend upward from base 801. Weir 803 may be comprised of awater-impermeable material. Mesh screen 804 may be attached to base 801and may extend upwardly above and outside of weir 803. Mesh screen 804forms a porous wall. In one embodiment, mesh screen 804 may be a wire ornylon mesh screen, with a mesh size that is larger than the expectedsediment particle size. Impermeable deck 805 may be attached to meshscreen 804 above the top of weir 803. Deck 805 forms an impermeable deckand has a small inlet hole 806, in which stormwater flows through. Thestormwater may be introduced from inlet line 702, through inlet device703, and into filtration chamber 701. In one embodiment, deck 805 may besloped so that the influent stormwater is directed toward hole 806.

Inlet device 703 may be adapted so that it moves with the level of thestormwater in filtration system 700. During operation, inlet device 703may be positioned such that the top of base 801 may be level with thebottom of inlet line 702. In this arrangement, the influent stormwatermay be directed into the filtration chamber 701 through hole 807. Weir803 may prevent unfiltered stormwater from bypassing inlet device 703.Weir 803 may also prevent unfiltered stormwater from backing up intoinlet device 703. During high flow events-which generally correspond toinfrequent operating conditions, such as those during flooding or athunderstorm or other high-intensity runoff events-water may pass overinlet device 703, through mesh screen 804, and flow downstream, toprevent the filtration system from backing up.

Referring to FIGS. 8 and 9A, inlet device 703 may also be positionedsuch that deck 805 may be level with the bottom of inlet line 702. Inthis arrangement, the influent stormwater flows simultaneously throughhole 806 into filtration chamber 701, and also through mesh screen 804,through elements 100 and into filtration chamber 701, thus backwashingelements 100. Referring to FIG. 8 and 9B, as the level of water in thefiltration chamber rises, the inlet device 703 may rise until the top ofbase 801 may be level with the bottom of influent line 702. The influentstormwater may be directed into the filtration chamber 701 through hole807, and normal filtration operation proceeds.

In normal operation, stormwater is introduced into filtration system 700via inlet line 702. The stormwater flows through inlet device 703 andfills filtration chamber 701. As filtration chamber 701 fills withwater, the aqueous portion of the stormwater permeates through eachelongated filtration element 100. Fiberglass batting 201, which isexposed to the stormwater, traps a substantial amount of the sediment inthe stormwater. As the aqueous portion flows through each elongatedfiltratable element 100, fiberglass batting 201 is pressed againstbacking mesh 202, forming a permeable filter bed. A deck 1000 separatesfiltration system 700 into two parts: a lower housing and an upperhousing. In one embodiment, deck 1000 may be impermeable. After thelower housing of filtration system 700 fills completely with stormwater,influent stormwater accumulates on inlet device 703 creating the drivingforces for stormwater to permeate through each elongated filtratableelement 100. The aqueous portion, after permeating through filter mat102, travels upward through elongated filtration element 100 and outholes 402 in filtration cartridge 400. Deck 1000 separates the influentstormwater from the filtrate. The filtrate then flows downstream awayfrom the filtration system 700.

Referring to FIG. 10A, a filtration system with a backwashing mechanismis shown, according to one embodiment of the present invention. In thisembodiment, filtration system 700 has an inlet impermeable weir 1001 andan outlet impermeable weir 1002. In operation, the stormwater flowsthrough an inlet opening created by impermeable weir 1001 and fillsfiltration chamber 701. Impermeable weir 1001 separates the influentstormwater from the filtrate. As filtration chamber 701 fills withwater, the aqueous portion of the stormwater permeates through eachelongated filtration element 100. The filtrate then accumulates abovedeck 1000 until it overflows outlet impermeable weir 1002 and exitssystem 700. Outlet impermeable weir 1002 allows for a level of filtrateto accumulate above deck 1000. When flow stops, the stormwater thatremains in lower chamber of filtration system 700 drains down throughinfiltration, connection to a dry well, or any other drain-downmechanism. As the water level in the lower chamber drops, the filtratethat is accumulated above deck 1000 flows downward through eachfiltration cartridge 400, backwashing each elongated filtratable element100 and removing any trapped sediment.

Referring to FIG. 10B, in another embodiment, inlet line 702 may feeddirectly into filtration chamber 701 beneath deck 1000. In thisembodiment, inlet line 702 would be positioned, in relation tofiltration chamber 701, so that a sufficient hydraulic head is createdto cause stormwater to flow through elongated filtratable elements 100and out outlet line 704. In general, this will require inlet line 702 tobe positioned at a height above filtration chamber 701 and outlet line704. For example, inlet line 702, at some point upstream of filtrationchamber 701, may be elevated above filtration chamber 701 and then slopedownward and connect to filtration chamber 701 below deck 1000.

Referring to FIG. 11, a filtration system with a backwashing mechanismis shown, according to another embodiment of the present invention. Inthis embodiment, filtration system 700 has a plurality of filtrationcartridges 400 with each cartridge 400 being equipped with its ownbackwashing valve assembly 1200. Referring to FIG. 12A, valve assembly1200 may generally include five components: a cartridge cover 1201, arelease valve 1202, a float 1203, a hole 1204, and a tether 1205. Ingeneral, valve assembly 1200 enables each elongated filtratable element100 to be backwashed between rain events in order to remove trappedsediment.

Cartridge cover 1201 may be adapted so that it sealably and removablycovers each filtration cartridge 400 in filtration system 700. Tether1205 attaches release valve 1202, which may be pivotally attached tocartridge cover 1201, to float 1203. Release valve 1202 may have a plugthat fits into hole 1204. Valve assembly 1200 has two primary operatingpositions: a generally closed position, as shown in FIG. 12A, and anopen position, as shown in FIG. 12B.

Referring to FIGS. 13 and 14, filtration system 700 is in an operatingposition where stormwater has completely filled the lower housing and asmall amount of filtrate has accumulated above each valve assembly 1200.In normal operation, not the backwashing operation, release valve 1200may be slightly forced open by the filtrate flowing upward throughfiltration cartridge 400 so that filtrate accumulates on deck 1000before it flows out of filtration system 700 via outlet 704. In oneembodiment, as shown in FIG. 13, each valve assembly 1200 may beseparated using a partition 1300 so that each filter cartridge 400 mayhave its own “tank” of filtrate for later use during backwashing. Inthis embodiment, outlet line 704 (not shown) may be at the level of thetop of partition 1300.

During normal operation, filtrate flows up through each elongatedfiltratable element 100 as usual. When the flow of influent stormwaterstops, release valve 1202 closes to prevent any of the filtrate that hasaccumulated on the upper housing of filtration system 700 from drainingdown through each filtration cartridge 400. When flow stops, thestormwater that remains in lower chamber of filtration system 700 drainsdown through infiltration, connection to a dry well, or any otherdrain-down mechanism. Float 1203 travels downward as the stormwater inthe lower housing is drained. When the water level in the lower chamberdrops to the desired level, release valve 1202 may be pulled open byfloat 1203 via tether 1205. In one embodiment, tether 1205 may be longenough to allow float 1203 to reach a level below each elongatedfiltratable element 100. When release valve 1202 opens, the “tank” ofaccumulated filtrate above each filtration cartridge 400 flushesdownward, backwashing each filtratable element 100 and removing anytrapped sediment.

Referring to FIG. 15, deck 1000 for filtration system 700 is shownaccording to one embodiment. In this embodiment, deck 1000 may begenerally described as an insert that securely fits into filtrationchamber 701. Deck 1000 may divide filtration chamber 701 into an upperchamber above deck 1000, and a lower chamber below deck 1000. Deck 1000may have one or more holes for mounting one or more filtrationcartridges (not shown). Further, deck 1000 may have a ridge 1404attached to or integrally formed with the top surface of impermeabledeck 1000. Ridge 1404 may form perimeter on deck 1000. Ridge 1404 maygenerally surround holes 1402. Ridge 1404 acts as an outlet weir for thefiltered water that filters through each filtration cartridge 400. Ridge1404 may be of any suitable height and thickness. Water may exitfiltration system 700 by flowing over ridge 1404 and onto anotherportion of deck 1000, proceeding downstream via outlet line 704.

Deck 1000 may also have a skirt 1406. Skirt 1406 may be attached to orintegrally formed with the bottom surface of deck 1000. Skirt 1406 mayextend below deck 1000 at some distance. Skirt 1406 may substantiallysurround or entirely surround elongated filtratable elements 100 thatreside in the lower chamber of filtration system 700. Skirt 1406 may beof any suitable length; it may extend beyond, be of the same length, orbe shorter than elongated filtratable elements 100.

Referring to FIG. 16, another embodiment of filtration system 700 isshown according to one embodiment. In this embodiment, deck 1000, havingridge 1404 and skirt 1406, may be installed into filtration chamber 701.Deck 1000 may have a substantially circular outer perimeter and may besized to fit within the walls of filtration chamber 701. Deck 1000 mayalso be shaped to provide access for maintenance. The access way may beof any shape and depth. The access way may allow for inspecting andmaintaining filtration system 700. For example, a ladder, or ladderrungs, may be located within the access way.

In this embodiment, inlet line 702 may be located below deck 1000. Inletline 702 may be located above the bottom of skirt 1406. Inlet line 702may be tangential to filtration chamber 701. Therefore, influent may beintroduced tangentially into filtration chamber 701 below deck 1000.Influent may be directed in a circular path around skirt 1406, which mayallow coarse sediments to settle at the bottom of filtration chamber701, and floatable pollutants to rise and be trapped underneath deck1000 and outside of skirt 1406. In other words, influent is introducedinto filtration system 700 via tangential inlet line 702. Thisarrangement causes the influent to “swirl” around skirt 1406, eventuallyflowing under skirt 1406, then upward and through elongated filtrationelements 100. In this embodiment, each filtration cartridge 400 is shownas being covered by lid 404. The aqueous portion flows through eachelongated filtratable element 100, through hole 406 in lid 404, and ontodeck 1000. Filtered water accumulates above deck 1000 until it reaches alevel to overflow ridge 1404. Water then exits filtration system 700through outlet line 704.

Referring to FIG. 17, one or more filtration cartridges 400 may beinstalled outside ridge 1404. For example, filtration cartridge 410 maybe located outside of ridge 1404. This embodiment allows for backwashingof elongated filtratable elements 100. When flow subsides from inlet702, water that has accumulated above deck 1000 and inside of ridge 1404then flows backwards through filtration cartridges 400 located inside ofridge 1404. The water flows downward, through each elongated filtratableelements 100 and into the lower portion of filtration chamber 701.Because there is one or more filtration cartridges 400 located outsideof ridge 1404, water then flows upward through one or more filtrationscartridges 400 installed outside of ridge 1404. Therefore, thisembodiment allows for filtration cartridges 400 that are located insideof ridge 1404 to be backwashed with filtered water.

Referring to FIG. 18, a bottom view of one embodiment of filtrationsystem 700 is shown. This embodiment shows that skirt 1406 surroundselements 100 from each filtration cartridge 400, even the one or morefiltration cartridges 400 that may be installed outside of ridge 1404.In another embodiment, skirt 1406 may not surround the fitratableelements 100 from each filtration cartridge. A portion of skirt 1406 mayalso define the access way.

Example

An experiment was conducted using five filtration cartridges, eachhaving eighteen elongated filtratable elements, for a total of 90elements. Each elongated filtratable element was constructed by wrappingfilter mats around a flexible inner core, and enclosing the filter matsin a nylon screen. Each filtratable element was 0.75″ in diameter and48″ long. The elongated filtratable elements tested had a surface areaof about 90 square feet. The filtration cartridges were placed inside a3′ diameter filtration chamber. With less then 5 inches of headloss, theprototype filtration system was able to remove over 5 kg of sil-co-sil106 (a standard fine sediment mixture) from the influent water having aflow rate of 1 L/s and a sediment concentration of 300 mg/L. The filtercartridge occupied approximately 1 square foot of area in an impermeabledeck separating the unfiltered and filtered water. The effluent waterstream had a sediment content less than 20% of the influentconcentration. It is reasonable to assume, based on these results, thatthis type of device could remove fine sediment for the runoff generatedby an acre of impervious area, be contained in a chamber less than 10feet in diameter, and last for over 1 year before the filter had cloggedor needed to be replaced. The total suspended solid removal, or sedimentremoval, efficiency was 90-92%.

It will be readily understood by those persons skilled in the art thatthe present invention is susceptible to broad utility and application.Many embodiments and adaptations of the present invention other thanthose herein described, as well as many variations, modifications andequivalent arrangements, will be apparent from or reasonably suggestedby the present invention and foregoing description thereof, withoutdeparting from the substance or scope of the invention.

Accordingly, while the present invention has been described here indetail in relation to its exemplary embodiments, it is to be understoodthat this disclosure is only illustrative and exemplary of the presentinvention and is made to provide an enabling disclosure of theinvention. Accordingly, the foregoing disclosure is not intended to beconstrued or to limit the present invention or otherwise to exclude anyother such embodiments, adaptations, variations, modifications orequivalent arrangements.

1. A system for removing suspended particles from a liquid, the systemcomprising: a filter chamber defining an internal chamber; a deckpositioned within the internal chamber and dividing the filter chamberinto an upper chamber and a lower chamber, the deck having a pluralityof holes formed therein, each hole adapted to receive a filtrationelement therein; and an inlet line for communicating an influent liquidto the filter chamber at a location that is below the deck; wherein theinlet line is positioned such that the influent liquid is introducedtangentially into the filter chamber.
 2. The system of claim 1, whereinthe filtration element comprises at least one elongated filtratableelement and a lid.
 3. The system of claim 1, wherein the filtrationelement comprises a filtration cartridge.
 4. The system of claim 1,wherein the deck further comprises a ridge attached to a top surface ofthe impermeable deck.
 5. The system of claim 4, wherein the ridge formsa perimeter that encloses at least one of the filtration cartridges. 6.The system of claim 1, wherein the deck further comprises a skirtattached to a bottom surface of the deck.
 7. A system for removingsuspended particles from a liquid, the system comprising: a filterchamber defining an internal chamber; a deck positioned within theinternal chamber and dividing the filter chamber into an upper chamberand a lower chamber, the deck having a plurality of holes formedtherein, each hole adapted to receive a filtration element therein; aninlet line for communicating an influent liquid to the filter chamber;and a ridge positioned on a top surface of the deck, wherein the ridgeforms a perimeter on the top surface of the deck.
 8. The system of claim7, wherein at least one of the filtration elements is positioned withinthe perimeter.
 9. The system of claim 7, wherein at least one of thefiltration elements is positioned outside the perimeter.
 10. The systemof claim 7, wherein the filtration element comprises at least oneelongated filtratable element and a lid.
 11. The system of claim 7,wherein the filtration element comprises a filtration cartridge.
 12. Thesystem of claim 7, wherein the system further comprises a tangentialinlet line for introducing liquid below the deck.
 13. The system ofclaim 7, wherein the system further comprises an outlet located abovethe deck.
 14. The system of claim 7, wherein the deck comprises anaccess way from the upper chamber to the lower chamber.
 15. A system forremoving suspended particles from a liquid, the system comprising: afilter chamber defining an internal chamber; a deck positioned withinthe internal chamber and dividing the filter chamber into an upperchamber and a lower chamber, the deck having a plurality of holes formedtherein, each hole adapted to receive a filtration element therein; aninlet line for communicating an influent liquid to the filter chamber;and a skirt positioned on a bottom surface of the deck.
 16. The systemof claim 15, wherein the inlet line introduces liquid tangentially intothe filter chamber outside of the skirt.
 17. The system of claim 16,wherein the inlet line is connected to the filter chamber above wherethe skirt terminates in the lower chamber.
 18. The system of claim 15,wherein the deck comprises a ridge positioned on a top surface of thedeck, the ridge forming a perimeter on the top surface of the deck. 19.The system of claim 18, wherein at least one of the filtration elementsis positioned within the perimeter.
 20. The system of claim 18 whereinat least one of the filtration elements is positioned outside theperimeter.
 21. The system of claim 15, wherein the skirt surrounds atleast one of the filtration elements.
 22. The system of claim 15,wherein the skirt surrounds all of the filtration elements.